Polarizing lens, eyewear, and method for manufacturing polarizing lens

ABSTRACT

A method for manufacturing a polarizing lens that includes a polarizing polyvinyl alcohol film arranged between two pieces of a lens base material. The method includes subjecting the polarizing lens to edging processing to prepare a polarizing lens where the polarizing polyvinyl alcohol film is exposed at least at a part of an edge surface of the lens, and applying hydrophobization treatment to the polarizing polyvinyl alcohol film exposed at the edge surface of the lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Division of application Ser. No. 15/028,646filed Apr. 11, 2016, which in turn is a national stage entry ofPCT/JP2014/077752 filed Oct. 17, 2014, which claims priority of JapanesePatent Application No. 2013-216303, filed Oct. 17, 2013. The disclosureof each of the prior applications is hereby incorporated by referenceherein in its entirety.

TECHNICAL FIELD

The present invention relates to a polarizing lens, eyewear includingthis polarizing lens, and a method for manufacturing a polarizing lens.

BACKGROUND ART

A polarizing lens has a light-shielding function and thus is often usedas a lens for sunglasses (including fashion glasses) withoutprescriptions for protection of eyes. The use of a polarizing lens isnot limited thereto but also includes a spectacle lens with aprescription.

Polarizing lenses described in Patent Literature 1 and Patent Literature2 include a polarizing film buried therein and is manufactured byinjecting a curable composition around the polarizing film and heatingto allow for curing thereof.

Meanwhile, in FIG. 5 and more of Patent Literature 3 also disclose aswimming goggle including a polarizing lens including a polarizing filmburied therein, more specifically, a polarizing lens where a polarizedfilter film is interposed between two layers of plastic or the like.

Meanwhile, frames of eyewear have various designs such as a full-rimtype, rimless type with no rim at an edge surface of a lens (including arimlon type), and a goggle type. Generally, a polarizing lens is formedinto a round shape, subjected to edging processing to process into alens shape of a frame, and attached to the frame; however, the lens maybe formed to fit the lens shape of the frame in advance. In either case,in a polarizing lens including a polarizing film buried therein, an edgesurface of the polarizing film is usually exposed at an edge surface ofthe lens.

Patent Literature 1: JP 2007-316595 A

Patent Literature 2: JP 2007-523768 W

Patent Literature 3: U.S. Pat. No. 6,676,257

The entire descriptions of Patent Literature 1 and English patent familymember US2009/091825A1, Patent Literature 2 and English patent familymember US2007/098999A, U.S. Pat. No. 7,767,304, and Patent Literature 3are hereby specifically incorporated as disclosures.

SUMMARY OF INVENTION

As a definition of terms, in the present invention and hereinafter, aterm polarizing lens means a lens of a meniscus shape where a polarizingfilm is arranged (interposed) between two pieces of a lens base materialwithout discriminating optical designs or lens power.

A term eyewear includes eyewear for eyesight correction where at leastone of lenses on the left and right attached to a frame is a lens(spectacle lens) having an eyesight corrective function that opticallysatisfies a prescription, namely spectacles, as well as various eyewearother than spectacles such as sunglasses (including fashion glasses) andgoggles. Further, sunglasses or goggles where at least one of lenses onthe left and right is a lens (spectacle lens) having an eyesightcorrective function that optically satisfies a prescription are alsoincluded in the term eyewear.

A term spectacle lens means a finished lens (both surfaces are finalprescription surfaces) or semifinished lens (only one surface is a finalprescription surface) having a meniscus shape, where a lens shape is inan uncut or cut state.

As for a frame, a type of frame where a rim (lens frame) is formedaround the entire periphery of a lens is defined as a full-rim frame anda type of frame where a part or all of an edge surface of a lens isexposed is defined as a rimless frame. All frames, as well as goggles,are included in either of these definitions. Therefore, a rimlon typehaving a rim bar, where a groove is formed in an edge surface of a lensand the rim bar is fitted to the groove part with nylon, syntheticresin, fine wire, or the like to retain the edge surface of the lens, isincluded in the rimless frame. Furthermore, a frame of a sports type orgoggle type is also classified by the above definitions depending on theaforementioned exposure state of an edge surface of a lens.

When a polarizing film is exposed at an edge surface of a polarizinglens as described above, water or alkaline cleaning liquid may permeatefrom the edge surface upon dying for processing, hard coat, polishingtreatment, washing or the like, which may result in melting anddeterioration of an outer periphery part of the polarizing film. Asimilar phenomenon may occur also with a polarizing lens included ineyewear used for water sports such as swimming goggles.

Moreover, even after a polarizing lens is attached to a frame, if theframe is a rimless frame, a polarizing film is exposed at a part withouta rim as described above and thus a similar phenomenon may occur.Therefore, usually, a full-rim type is selected as a frame design forspectacles or sunglasses including a polarizing lens. That is, a framedesign for a polarizing lens has an implicit constraint.

Meanwhile, even with a frame of a full-rim type, for example whenspectacles are dropped into water, water may permeate from a slight gapbetween the frame and edge surface of a polarizing lens, which mayresult in melting and deterioration part of an outer periphery of apolarizing film. With regard to this point, Patent Literature 3discloses that a sealing member of a ring shape is fitted to an outerperiphery part of a polarizing lens. However, when adhesion between anedge surface of the polarizing lens and sealing member is notsufficient, water may permeate from a slight gap between the edgesurface of the polarizing lens and sealing member, which may result inmelting and deterioration of an outer periphery part of the polarizingfilm.

Therefore, an object of the present invention is to provide a polarizinglens where deterioration of a polarizing film is suppressed.

As the polarizing film, usually, polyvinyl alcohol (hereinafter alsoreferred to as “PVA”) is impregnated in iodine or dichroic dye, which isthen formed into a film shape and extended along one axis direction touse a film obtained therefrom. This is because PVA is preferable as afilm material since it is superior in any of transparency, heatresistance, affinity with iodine or dichroic dye, and orientation uponextension. In the present invention and hereinafter, a polyvinyl alcoholfilm containing a dye component selected from a group consisting ofiodine and dichroic dye and showing a polarizing property is referred toas “polarizing polyvinyl alcohol film”.

The present inventors focused on a point that PVA that forms a film is aresin having a hydroxyl group and high hydrophilicity during repeatedexaminations for achieving the aforementioned object. As a result offurther repeated keen examinations, a new finding has been obtained thathydrophobization of a region of a polarizing polyvinyl alcohol filmexposed at an edge surface of a lens can prevent water or the like frompermeating into the outer periphery part of the polarizing polyvinylalcohol film, which can prevent deterioration of the polarizingpolyvinyl alcohol film.

The present invention has been completed based on the above finding.

One aspect of the present invention relates to a polarizing lensincluding a polarizing polyvinyl alcohol film arranged between twopieces of a lens base material, where the polarizing polyvinyl alcoholfilm includes a hydrophobic region having higher hydrophobicity thanother regions at least at a partial region of an outer periphery partincluding an edge surface thereof and the hydrophobic region is exposedat least at a part of an edge surface of the lens.

In one aspect, the hydrophobic region is formed by reaction between ahydroxyl group included in polyvinyl alcohol included in the region anda functional group having reactivity with the hydroxyl group at least atthe partial region.

In one aspect, the reaction is selected from a group consisting ofcross-linking reaction, dehydration reaction, and halogenation.

In one aspect, the reaction is cross-linking reaction between polyvinylalcohol and a cross-linking agent. In a further aspect, thecross-linking agent is aldehyde and the cross-linking reaction isacetalization.

Still further aspect of the present invention relates to eyewearincluding a frame and the lens attached to the frame.

In one aspect, the eyewear is spectacles.

Yet further aspect of the present invention relates to a method formanufacturing a polarizing lens including the steps of producing apolarizing lens where a polarizing polyvinyl alcohol film is arrangedbetween two pieces of a lens base material and the polarizing polyvinylalcohol film is exposed at least at a part of an edge surface of thelens and applying hydrophobization treatment to the polarizing polyvinylalcohol film exposed at the edge surface of the lens.

In one aspect, the hydrophobization treatment is performed by allowingthe polarizing polyvinyl alcohol film exposed at the edge surface of thelens to be in contact with a hydrophobizing agent including thefunctional group having reactivity with the hydroxyl group.

In one aspect, the hydrophobizing agent includes polyvinyl alcohol and acompound that may cause reaction selected from a group consisting ofcross-linking reaction, dehydration reaction, and halogenation.

In one aspect, the hydrophobizing agent is a cross-linking agent thatmay react with polyvinyl alcohol in a cross-linking manner. In a furtheraspect, the cross-linking agent is aldehyde and the cross-linkingreaction is acetalization.

In one aspect, the aforementioned method for manufacturing a polarizinglens includes a step of forming the polarizing lens by a castpolymerization method (casting method), which will be described later.In a still further aspect, a polarizing polyvinyl alcohol film arrangedin a forming mold in this step is applied with curved surface processingto deform into a curved surface.

In one aspect, the polarizing polyvinyl alcohol film having beensubjected to the curved surface processing is subjected to heatingtreatment to heat at a heating temperature of 105° C. to less than 150°C. and then arranged in a forming mold. Apply the heating treatment atthe above range of heating temperature after the curved surfaceprocessing is preferable from the following points.

In a polarizing lens produced by a cast polymerization method,deformation of the lens may cause astigmatism. This is due todeformation of a surface shape of the lens under influence ofdeformation of the polarizing film buried in the lens by heating duringa step of manufacturing. A wearer of spectacles observing an objectthrough spectacle lenses with astigmatism feels uncomfortableness ofwearing (e.g. blurred images) caused by astigmatism. Therefore, in orderto provide a spectacle lens having preferable wearing feeling,astigmatism should be prevented or mitigated.

Meanwhile, in the method for manufacturing a polarizing lens accordingto the above aspect, the polarizing film having been subjected to thecurved surface processing is heated at the heating temperature of 105°C. to less than 150° C. before arrangement in the forming mold. Heatingin this manner allows the polarizing film having been subjected to thecurved surface processing to be deformed (shrink) before arrangement inthe forming mold. This results in no shrinkage to deform the surfaceshape of the lens or a small level of shrinkage. This allows forproviding a polarizing lens with slight aberration.

In one aspect, the manufacturing method includes wetting the polarizingfilm before the curved surface processing.

In one aspect, the manufacturing method includes wetting, duringheating, the polarizing film before the curved surface processing,cooling the film, and subsequently performing the curved surfaceprocessing.

In one aspect, the cooling is performed by leaving the wetted polarizingfilm at the room temperature.

The present invention can provide a polarizing lens including apolarizing film of a high quality where deterioration of an outerperiphery part thereof is mitigated or prevented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of a left frame of rimless polarizing spectacles2 of a two-point type using a polarizing lens 1 according to one aspectof the present invention.

FIG. 2 is a perspective view explaining a state of an edge surface ofthe polarizing lens 1 in FIG. 1.

FIG. 3 is a cross-sectional view along a line A-A′ in FIG. 1.

FIG. 4 is a perspective view of rimless polarizing spectacles of arimlon type using the polarizing lens 1 according to one aspect of thepresent invention.

FIG. 5 is a front view of a left frame of the polarizing spectacles inFIG. 4.

FIG. 6 is a cross-sectional view along a line B-B′ in FIG. 5.

FIG. 7 is a perspective view of polarizing spectacles of a full-rim typeusing the polarizing lens 1 according to one aspect of the presentinvention.

FIGS. 8(A) to 8(C) are diagrams explaining curved surface processing ofa polarizing film.

FIG. 9 is a cross-sectional view of a polarizing film having beensubjected to the curved surface processing.

FIG. 10 is a cross-sectional view of a polarizing lens having aprotective part.

FIG. 11 is a cross-sectional view of a polarizing lens having aprotective part.

FIG. 12 is a diagram explaining a manufacturing flow of a polarizinglens of an example.

FIG. 13 is a cross-sectional view of mold forming molds used in anexample.

FIG. 14 is a cross-sectional view of a lens produced in an example aftermold release.

FIG. 15 is a picture, imaged by a digital camera, of a part cut out froma polarizing lens produced in an example 1 after a water resistance test(24 hours).

FIG. 16 is a picture, imaged by a digital camera, of a part cut out froma polarizing lens produced in a comparative example 1 after the waterresistance test (24 hours).

DESCRIPTION OF EMBODIMENTS

One aspect of the present invention relates to a polarizing lensincluding a polarizing polyvinyl alcohol film arranged between twopieces of a lens base material, where the polarizing polyvinyl alcoholfilm includes a hydrophobic region having higher hydrophobicity thanother regions at least at a partial region of an outer periphery partincluding an edge surface thereof and the hydrophobic region is exposedat least at a part of an edge surface of the lens. Hereinafter, theaforementioned polarizing lens will be further described in detail.

(Lens Base Material)

A lens base material is not specifically limited and may be a plasticlens base material such as acrylic resin, thiourethane-based resin,thioepoxy-based resin, methacrylate-based resin, allyl-based resin,episulfide-based resin, and polycarbonate resin. A molding method of thelens may a cast polymerization method or injection molding method. Thecast polymerization method is preferable. In either molding method,molding is performed such that the polarizing polyvinyl alcohol film (ora laminated film including this film as will be described later) isinterposed between the lens base materials. For example upon molding alens by the cast polymerization method, the polarizing polyvinyl alcoholfilm is arranged in a forming mold and thereafter polymerizationreaction of lens raw material liquid is carried out. A preferable aspectof the polarizing film arranged in the forming mold here may be apolarizing film applied with the curved surface processing as describedbelow and, more preferably, a polarizing film applied with the heatingtreatment at the aforementioned range of heating temperature after thecurved surface processing.

(Polarizing Film)

The polarizing lens includes a polarizing polyvinyl alcohol filmarranged between two pieces of the lens base material. The polarizinglens where the polarizing film is buried and interposed between twopieces of the lens base material can be preferably obtained by the castpolymerization method which is performed while the polarizing film isarranged in a forming mold. Details will be described later.

The polarizing film included in the polarizing lens is a polarizingpolyvinyl alcohol film, which is usually produced by, as describedearlier, extending a polyvinyl alcohol film containing iodine ordichroic dye. Incidentally, the polarizing polyvinyl alcohol film may besolely used as the polarizing film or may be used in the form of alaminated film where multiple layers including other layers arelaminated. One example of a film that can form the multilayer film is atriacetylcellulose (TAC) film. The TAC film may function as a protectivelayer. For example, a laminated film of two or three layers where theTAC film is provided on one surface or both surfaces of the polarizingpolyvinyl alcohol film may be used as the polarizing film. Hereinafter,the polarizing polyvinyl alcohol film or the laminated film includingthis film is also referred to as “polarizing film”.

The above films may be commercial products or produced by a knownmethod.

The thickness of a polarizing film is not specifically limited.Preferably, the thickness is set such that the curved surface processingof the film can easily be performed. The curved surface processing willbe described later. For example, the thickness of the single-layer ormultilayer polarizing film is preferably approximately 10 μm to 500 μm.This is because a thickness of 10 μm or more provides high rigidity andease of handling while a thickness of 500 μm or less provides ease uponthe curved surface processing of the film.

In the above polarizing lens, the polarizing polyvinyl alcohol film is,solely or in the form of the laminated film as described above,interposed between two pieces of a lens base material. Furthermore, anedge surface or at least a part of an outer periphery part including theedge surface of the polarizing polyvinyl alcohol film is exposed atleast at a part of an edge surface of the lens. Usually, a polarizinglens where a part of the polarizing polyvinyl alcohol film is exposed inthis manner is prone to deterioration by water or alkaline cleaningliquid. Meanwhile, the aforementioned polarizing lens allows forsuppressing deterioration since at least a part of the exposed region,preferably all of the exposed region, is hydrophobized.

As the hydrophobization treatment, any treatment that is capable ofhydrophobizing polyvinyl alcohol can be used without limitation. Onespecific aspect is treatment to cause reaction between a hydroxyl groupthat allows polyvinyl alcohol to be hydrophilic and a functional grouphaving reactivity with the hydroxyl group (hereinafter referred to as“treatment 1”). This allows the treated region to be hydrophobized witha content ratio of hydroxyl group lower than that in untreated regions.Another specific aspect is treatment to apply a water repellent agent tothe edge surface of the lens including the part where polarizedpolyvinyl alcohol is exposed (hereinafter referred to as “treatment 2”).

The treatment 1 and treatment 2 are performed on a region including theedge surface of the lens and thus also referred to as “edge surfacetreatment” hereinafter. Hereinafter, each of the treatment will befurther described in detail.

Hydrophobization Treatment by Treatment 1

The treatment 1 is to cause reaction between a hydroxyl group in thepolyvinyl alcohol film that forms the polyvinyl alcohol film and afunctional group having reactivity with the hydroxyl group. Contactbetween a compound including a functional group having reactivity withthe hydroxyl group (hereinafter referred to as “hydrophobizing agent”)and the polarizing polyvinyl alcohol film exposed at the edge surface ofthe lens allows for reaction between polyvinyl alcohol and thefunctional group of the hydrophobizing agent. The polyvinyl alcohol filmexposed at the edge surface of the lens can be caused to be in contactwith the hydrophobizing agent by, for example, a method to mix thehydrophobizing agent with a solvent and, as necessary, an additive suchas a reaction catalyst to obtain a solution (hydrophobizing agentsolution) and to immerse the edge surface of the lens or the entire lensin the hydrophobizing agent solution or a method to apply thehydrophobizing agent solution to the edge surface of the lens by a knownapplication method. One preferable example of application devices is acoating liquid applicator described in detail in Japanese Patent No.5149809. When there is a possibility that immersion of a part or all ofthe lens in the hydrophobizing agent solution may result indeterioration of an optical surface of the lens due to the solvent ofthe hydrophobizing agent solution, it is preferable to seal the opticalsurface of the lens with a protective film or the like (e.g. aluminumfoil) and then to perform immersion. When the hydrophobizing agentsolution is an aqueous solution, usually, the treatment can be performedwithout sealing.

The hydroxyl group contributes to hydrophilicity of the polarizingpolyvinyl alcohol film. Therefore, causing reaction between the hydroxylgroup of polyvinyl alcohol and other functional groups results inpartial hydrophobization of the polarizing polyvinyl alcohol film,thereby allowing for forming a hydrophobic region at a part of thepolarizing polyvinyl alcohol film exposed at the edge surface of thelens or the outer periphery part including this part. A preferablespecific aspect of the reaction between the hydroxyl group included inpolyvinyl alcohol and other functional groups may be cross-linkingreaction, dehydration reaction, halogenation, or the like. Hereinafter,each of the reactions will be further described; however, the presentinvention is not limited to specific aspects. Note that, the dehydrationreaction also includes dehydration condensation reaction. Further, thecross-linking reaction includes an aspect where a cross-linkingstructure is formed by dehydration condensation reaction.

Polyvinyl alcohol is a polymer represented by —[CH₂CH(OH)]n- (where n isthe number of recurring units). Cross-linking two hydroxyl groups (—OH)with a cross-linking agent allows for lowering hydrophilicity ofpolyvinyl alcohol and thereby forming a hydrophobic region. For example,when formaldehyde HC(═O)H is used as the cross-linking agent,dehydration condensation reaction is carried out between formaldehydeand the two hydroxyl groups, thereby forming a cross-linking structureof —O—(CH₂)—O— at a side chain of polyvinyl alcohol (acetalization).This as a known reaction as synthetic reaction of a so-called syntheticfiber vinylon. Acetalization may be performed with not limiting toformaldehyde but also with aldehyde such as acetaldehyde, glyoxal, andglutaraldehyde. Alternatively, a known cross-linking agent may be usedsuch as melamine-formalin-based resin cross-linking agent,urea-formalin-based resin cross-linking agent, and epoxy-basedcross-linking agent.

The dehydration reaction may be dehydration by alcohol (etherification),dehydration by silanol (silyl etherification), or dehydration bycarboxylic acid (esterification). Further, halogenation may be performedby using a known halogenation agent such as hydrogen halide (e.g. HBr).

The above reactions are known and thus various reaction conditions suchas a reaction temperature, reaction time, amount of hydrophobizing agentused, amount of a reaction reagent or additive used such as reactioncatalyst, acid, and base that is arbitrarily used can be determinedbased on known techniques. For example, acetalization can be performedby immersing the polarizing lens in the hydrophobizing agent(cross-linking agent) solution with a temperature of 40 to 100° C. forapproximately ten minutes to one hour with presence of an acid catalyst.As the acid catalyst, hydrochloric acid, sulfuric acid, or the like isusually used but not specifically limited thereto. Depending on thecross-linking agent, a reaction may proceed with presence of a basiccatalyst. Further, dehydration is usually carried out under acidicconditions. After the hydrophobization treatment under acidic conditionsis performed, neutralization may be arbitrarily carried out using abase. Conversely, after the hydrophobization treatment is performedunder basic conditions, neutralization may be arbitrarily carried outusing an acid.

The hydrophobic region formed by the above treatment 1 may be formedonly at the part of the polarizing polyvinyl alcohol film interposedbetween two pieces of a lens base material and exposed at the edgesurface of the lens or at an outer periphery part extending toward aninner part of the film with a predetermined width where thehydrophobizing agent solution permeates from the exposed part. Since thefilm is interposed between two pieces of a lens base material,permeation of the hydrophobizing agent solution can be stopped at theouter periphery part of the film. When the part exposed at the edgesurface of the lens is hydrophobized, permeation of water or the likeinto the film can be prevented and thus a width from the edge part ofthe film of the hydrophobic region is not specifically limited.

Hydrophobization Treatment by Treatment 2

The treatment 2 is to apply water repellent agent to the edge surface ofthe lens including the part where the polarizing polyvinyl alcohol filmis exposed. The water repellent agent may be diluted by a dilutionsolvent as necessary, which may be used as application liquid. Thetreatment 2 allows the polarizing polyvinyl alcohol film exposed at theedge surface of the lens to be protected by water repellent coating andthereby hydrophobized. Application of the water repellent agent may beperformed on at least the part where the polarizing polyvinyl alcoholfilm is exposed at the edge surface of the lens; however, application onthe entire surface of the edge surface of the lens including that partis also possible.

As the water repellent agent, a known water repellent agent may be usedwithout limitation. Examples include a fluorine-containing polymer or apolymerizable compound that can form fluorine-containing polymer(monomer, oligomer, prepolymer, or the like, for example perfluoroalkylacrylate). When a polymerizable compound is used as the water repellentagent, usually, a polymerization initiator corresponding to a type ofthe polymerizable compound is added to the water repellent agentapplication liquid and the water repellent agent is applied. Thereafter,curing treatment corresponding to the type of the polymerizable compoundis performed (heating, irradiation with light, etc.). Moreover, anadditive corresponding to a desired function may be arbitrarily added tothe application liquid. For example, adding an ultraviolet lightabsorbent to the application liquid can prevent deterioration of theouter periphery part of the polarizing polyvinyl alcohol film due towater or the like and also provide, to the edge surface of the lens,coating having a function to prevent deterioration of the edge surfaceof the lens due to ultraviolet rays. The application liquid including anultraviolet light absorbent can be prepared referring to descriptionsin, for example, the description of Japanese Patent No. 5149809.

Furthermore, in order to enhance adhesion between the water repellentcoating formed by the treatment 2 and the edge surface of the lens, aknown primer (adhesive layer) may be provided to the edge surface of thelens before the hydrophobization treatment by the treatment 2. Moreover,a protective layer such as acrylic coating may be provided over thewater repellent coating. Further, the protective layer may also beprovided on the edge surface of the polarizing lens having been appliedwith the treatment 1.

As described above, frames of eyewear include a full-rim type andrimless type. Eyewear with the polarizing lens attached to a rimlessframe is prone to deterioration due to permeation of water or the likesince the edge surface of the polarizing lens is exposed at a rimlesspart. Contrary to this, in the lens applied with the aforementionedhydrophobization treatment, deterioration due to permeation of water orthe like can be suppressed with presence of the hydrophobic region evenin a state without protection by the rim.

Hereinafter, specific aspects of spectacles where the polarizing lensaccording to one aspect of the present invention is attached to arimless frame will be described with reference to the drawings. However,the present invention is not limited to the following specific aspects.

FIG. 1 is a front view of a left frame of rimless spectacles 2 of atwo-point type including a polarizing lens 1 according to one aspect ofthe present invention. FIG. 2 is a perspective view explaining a stateof an edge surface of the polarizing lens 1 illustrated in FIG. 1. FIG.3 is a cross-sectional view along a line A-A′ in FIG. 1.

In FIGS. 1, 2, and 3, a two-point frame mounted with the polarizing lens1 according to one aspect of the present invention has a generalstructure. The frame has a structure where temples (not illustrated) andpads 3 support the spectacles at the face (nose part) and head (earparts) such that an optical axis of the lens and vision of a pupilcentral position is not shifted.

Each of two lens locking parts 4 a and 4 b is a connecting part forholding the lens and connecting the lens with a bridge 5 and hinge 6.Holding the polarizing lens 1 is performed by boring the lens from thefront and back of the optical surface thereof and fixing with the lenslocking parts 4 a and 4 b via screws (not illustrated). One end otherthan the end holding the lens of each of the lens locking parts 4 a and4 b is connected to the bridge 5 and hinge 6, respectively. The bridge 5is a part to connect the lenses on the left and right. The hinge 6 is apart to connect the temple and also has a function to open and close thetemple. Note that the structure of the frame is symmetrical.

As illustrated in FIG. 2, the polarizing lens 1 according to one aspectof the present invention has a structure where a polarizing film 7 isinterposed within the lens. As an example, the lens is a plastic lensmade of diethylene glycol bis-allyl carbonate formed by the castpolymerization method (casting method) with a lens power of 1.00dioptres.

The polarizing film 7 used in this polarizing lens 1 is the polarizingpolyvinyl alcohol film. In an outer periphery region (including an edgesurface of the outer periphery) of the polarizing film 7, a hydrophobicregion 72 where a hydroxyl group of polyvinyl alcohol has been reactedwith other functional groups is formed unlike an inner region 71. Thishydrophobic region 72 has a lower content ratio of hydroxyl group thanthat of the inner region 71 due to the above reaction and thus has ahigher hydrophobicity than that of the inner region 71. As onepreferable example, the hydrophobic region 72 is a region wherepolyvinyl alcohol is acetalized by aldehyde. Further, in one aspect, thepolarizing film 7 is applied with the curved surface processing toapproximate the film to a convex surface curve of a convex surface part101 of the polarizing lens 1 before molding by the cast polymerizationmethod. (Refer to FIG. 9 which will be described later.)

Furthermore, the polarizing lens 1 is applied with surface treatment, onthe optical surface thereof, such as a hard coat and formation of ananti-reflection film and cut into a predetermined lens shape of aspectacle frame (edging processing) selected by a wearer. Further, anedge surface of an outer periphery 102 of the polarizing film 7 exposedat an edge surface part of the lens 103 is applied with thehydrophobization treatment while other parts of the edge surface part ofthe lens 103 is transparent and applied with mirror-finishing. The edgesurface of an outer periphery 102 of the polarizing film 7 exposed at anedge surface part of the lens 103 is applied with the aforementionedhydrophobization treatment (edge surface treatment).

As other specific aspects, FIGS. 4, 5, and 6 are diagrams explainingrimlon spectacles 8 where the polarizing lens according one aspect ofthe present invention is mounted to a general rimlon frame.

A point where a rimlon frame 9 is different from the two-point frame isthe support structure of the lens formed by a rim bar 10 and a lenssupporting member 11.

The lens supporting member 11 (e.g. nylon fiber or metal fine wire)fitted to a fitting groove included in the whole circumference of theedge surface of the lens supports the lens 1 while the rim bar 10positioned at an eyebrow part latches the supporting member 11 and therim bar 10 hangs the polarizing lens 1. The rim bar 10 includes a rimformed in an upper part of the lens corresponding to the eyebrow partand a locking portion arranged to fix the lens supporting member (notillustrated). One end of the rim bar 10 is connected to abridge 51 whilethe other end is connected to a hinge 61.

As illustrated in FIG. 6, the edge surface part of the polarizing lenshaving been subjected to the edge surface treatment as described in FIG.1 is further applied with grooving processing as a postprocessing withthe lens supporting member 11 fitted to a formed groove. The polarizingfilm 7 in the polarizing lens 1 is applied with the hydrophobizationtreatment similarly to the polarizing film included in theaforementioned rimless spectacles 2 of the two-point type and thusincludes the hydrophobic region 72 having higher hydrophobicity thanthat of the inner region 71 in an outer periphery region. Otherstructures of the lens is similar to those of the aforementionedspecific aspect. As one example, in the present aspect, the polarizinglens is a sunglasses type with a lens power of 0.00 dioptres with noprescription.

The aspect where the polarizing lens according to one aspect of thepresent invention is attached to the rimless frame has been describedabove; however, producing eyewear such as spectacles by attaching thepolarizing lens according to one aspect of the present invention to afull-rim frame is of course possible.

FIG. 7 is a diagram explaining full-rim spectacles 80 where thepolarizing lens according to one aspect of the present invention ismounted to a general full-rim frame. The full-rim spectacles 80 includethe polarizing lens 1 fitted to a full-rim frame 81. In the full-rimspectacles 80, even when water or the like permeates from a slight gapbetween the edge surface of the polarizing lens 1 and the full-rim frame81, the lens applied with the aforementioned hydrophobization treatmentcan be suppressed of deterioration by permeation of water or the likedue to presence of the hydrophobic region.

Furthermore, eyewear including the polarizing lens according to oneaspect of the present invention is also suitable for eyewear for watersports such as swimming goggles. Even when water permeates from a slightgap between the edge surface of the polarizing lens and a frame,deterioration can be suppressed as described above. Moreover, in eyewearincluding the polarizing lens according to one aspect of the presentinvention, a sealing member of a ring shape can be fitted to an outerperiphery part of the polarizing lens as described in Patent Literature3. Contrary to this, even when adhesion between the edge surface of thepolarizing lens and sealing member is not enough, the lens applied withthe aforementioned hydrophobization treatment can be suppressed ofdeterioration due to permeation of water or the like due to presence ofthe hydrophobic region.

(Curved Surface Processing of Polarizing Film)

Next, the curved surface processing of a polarizing film that can beperformed in a suitable manner in the method for manufacturing apolarizing lens according to one aspect of the present invention will bedescribed.

Two pieces of the lens base material interposing the polarizing filmhave a surface on an object side (convex surface) on one side and asurface on an eyeball side (concave surface) on the other side. Thepolarizing film having been subjected to the curved surface processingis arranged in a forming mold, thereby allowing for burying thepolarizing film between two pieces of the lens base material along acurved surface shape of the lens. Preferably, the polarizing film issubjected to the curved surface processing by a press molding methodwhile the polarizing film is made correspond to a molding surface shape(concave surface shape) of an upper mold.

For example, the polarizing film of a plane-shaped sheet is interposedby a pressing molding device including a temperature adjusting means(heater, cooling medium, etc.), pressing means, and a forming mold(matrix) where a male mold and female mold form a pair, thereby pressingand subjecting the polarizing film to the curved surface processing toprocess into a shape of a surface of the forming mold. As the male moldand female mold, those having a spherical molding surface are preferablefor use. The spherical surface is not a complicated shape and thus doesnot require special pressing device but allows for use of an ordinarypressing molding device. Therefore, curving can be easily performed.

FIG. 8(A) is a diagram illustrating a curved surface processing plate ofa male molding part. Sign 110 represents a film member of a plane shapeand sign 160 represents the curved surface processing plate. The curvedsurface processing plate 160 is formed by a processing base part 160 amade of ceramic with heat resistance and matrix parts 161 (161 a and 161b) of spherical glass molds.

The curvature of a curved surface of the matrix part 161 is setaccording to a base curve of a refractive surface of the convex surfaceside of the lens to be produced.

The film member 110 of a flat plate shape which is the polarizingpolyvinyl alcohol film cut into a rectangular shape is place on thismatrix part of male mold. Pressing by a pressing means having the matrixpart of female mold (not illustrated), for example at a room temperature(approximately 20 to 25° C.) results in transferring the shapes ofcurved surfaces 112 a and 112 b to the polarizing film, therebyobtaining the polarizing film having curved surfaces 114 a and 114 b.

It is preferable to wet the polarizing film before performing the curvedsurface processing, which enhances properties of transferring a shapefrom the matrix parts. Wetting treatment can be performed by a methodsuch as leaving the polarizing film in a humidistatic high temperaturedevice for a predetermined period of time or spraying the polarizingfilm with water in a mist state. Wetting can be performed in a heatingatmosphere of approximately 50 to 90° C.

The wet polarizing film is preferably cooled since the curved surfaceprocessing is performed while most of water absorbed is retained in thefilm. For example, the polarizing film removed from the humidistatichigh temperature device is left at a room temperature (approximately 20to 25° C.) as it is, thereby cooling the polarizing film.

In one preferable aspect, the polarizing film having been subjected tothe curved surface processing is then heated under a heating temperatureof 105° C. to less than 150° C. Note that the heating temperature withregard to the polarizing film subjected to the curved surface processingrefers to the temperature of the atmosphere where the heating treatmentis performed. Heating the polarizing film having been subjected to thecurved surface processing before arrangement in the forming moldprevents deformation of the polarizing film. As a result, deformation ofa surface of the polarizing lens, especially deformation of a surface onthe object side can be prevented. Here, a heating temperature of 105° C.or more can preferably prevent deformation while a heating temperatureof less than 150° C. can prevent occurrence of color changes ordistortion of the polarizing film. The heating temperature is preferably120° C. or more, further preferably 130° C. or less. The heatingtreatment can be performed in the atmosphere.

Various methods can be employed as the heating method. In one aspect,the polarizing film is placed in a hot air circulating oven heated tothe aforementioned temperature and thereby subjected to heat air forheating until the polarizing film shrinks enough.

When the film member 110 is subjected to the curved surface processingas illustrated in FIG. 8(B), a glass mold 160 and the film member 110are preferably not separated but heated together. That is, thepolarizing film having been subjected to the curved surface processing(film member 110) is retained by the curved surfaces 161 of the glassmold 160, thereby heated. Since the polarizing film extended along oneaxis has different levels of shrinkage depending on directions, a shapeof the curved surface may change from a shape having been set. Contraryto this, retaining by the curved surfaces 161 of the glass mold 160allows for shrinkage of the film member 110 according to a shape of thecurved surface 161 of the glass mold 160. Therefore, molding can beperformed with a more accurate curvature or shape of the curved surfaces112 than in the case of heating without the glass mold 160.

Next, as illustrated in FIG. 8(C), the film member 110 is cut along abroken line K in FIG. 8(C). In this manner, as a cross-section isillustrated in FIG. 9, the polarizing film 7 having been subjected tothe curved surface processing to have a convex shape can be obtained.

By arranging the polarizing film applied with the curved surfaceprocessing described above in the forming mold and forming the lens by acasting method, the polarizing lens where the polarizing film havingbeen subjected to the curved surface processing is interposed betweentwo pieces of the lens base material can be obtained. This polarizinglens is usually subjected to the surface treatment and edging processingand thereafter applied with the aforementioned hydrophobizationtreatment. Fitting into a frame after the hydrophobization treatmentresults in spectacles or sunglasses including the polarizing lens asdescribed above.

Also in another aspect, in order to further suppress deterioration of anouter periphery part of the polarizing film, a protective part can beprovided to an edge surface of the lens after the hydrophobizationtreatment. Specific aspects of the polarizing lens provided with such aprotective part are illustrated in FIGS. 10 and 11 (cross-sectionaldiagrams).

The protective part illustrated in FIGS. 10 and 11 is fitted to a groovepart formed in a part of the edge surface of the polarizing lens wherethe polarizing film is exposed.

A protective part 301 illustrated in FIG. 10 includes a covering partwhere a fitting part to be fitted to a groove part 302 is covered forthe entire periphery of the edge surface of the polarizing lens. Thecovering part is provided to have substantially the same width as thewidth of the edge surface. Moreover, the protective part 301 is fittedto the groove part and thus is not shifted and capable of covering andprotecting the polarizing film in a secured manner. As illustrated inFIG. 10, the protective part 301 is not provided to a surface on theobject side or a surface on the eyeball side of the polarizing lens andthus appearance of the spectacles is not impaired.

A protective part 401 illustrated in FIG. 11 includes a fitting part, tobe fitted to a groove part 402, which does not protrude from an edgesurface of the polarizing lens. Providing the fitting part in such amanner does not change a shape of an outer periphery of the lens.Therefore, appearance of spectacles does not change because of theprotective part.

As a material of the protective part, materials that can be used as thelens base material such as acrylic resin, thiourethane-based resin,thioepoxy-based resin, methacrylate-based resin, allyl-based resin,episulfide-based resin, or polycarbonate resin or silicone resin may beused. When the protective part is formed by the same material as that ofthe lens base material, the lens base material and protective part canbe integrated, thereby allowing the protective part to be inconspicuous.

EXAMPLES

Hereinafter, the present invention will be further described based onexamples. However, the present invention is not limited to aspectsillustrated in the examples.

Example 1

FIG. 12 is a diagram explaining a manufacturing flow of a polarizinglens of an example. The polarizing film is applied with the curvedsurface processing before arrangement in the forming mold. Detailsthereof are as described earlier. The curvature of the curved surface ofthe matrix part 161 was set according to a base curve (6 base) of therefractive surface of the convex surface side of the lens to beproduced.

As a molding method of the lens, a casting method was used. The castingmethod is a molding method to, as illustrated in FIG. 13, performpolymerization curing of a lens monomer within a cavity 204 formed by anupper mold 201, lower mold 202, and a sealing member 203 to adjust adistance between the upper and lower molds and to determine a lensthickness and to obtain a lens after mold release. Sign 205 represents aclamping member, made of an elastic body such as a spring, to clamp andfix the upper and lower molds. Incidentally, a state where the cavity204 is formed by the upper mold 201, lower mold 202, sealing member 203,and clamping member 205 is referred to as mold forming molds.

(Assembly of Mold Forming Molds)

The forming mold (mold forming molds) used in the casting method wasassembled in the following manner.

First, the polarizing film 7 having been subjected to the curved surfaceprocessing was allowed to be retained by a polarizing film mounting partof the gasket 203, thereby prepared the gasket 203 attached with thepolarizing film.

Next, in the gasket, the upper mold 201 was arranged opposite to aconvex surface side of the polarizing film while the lower mold 202 wasarranged opposite to a concave surface side of the polarizing film 7such that a distance between the upper mold 201 and lower mold 202 formsa predetermined cavity. When the cavity was formed, material propertiessuch as polymerization shrinkage of a lens monomer (lens raw materialliquid) were considered. As a result, an interval between the upper andlower molds was set such that a predetermined lens thickness based on alens design is satisfied.

(Injection of Monomer, Heating/Curing, and Mold Release)

A lens monomer was stirred and subjected to vacuum defoaming and theninjected to the assembled forming mold. Thereafter, the forming mold wasplaced in a heating furnace (atmosphere polymerization furnace) andsubjected to temperature elevation in the heating furnace from 30° C. to120° C. in 21 hours, thereby heated and cured the lens monomer.

After the heating and curing, the forming mold was removed from theheating furnace. The gasket 203 was then separated and the lens wasremoved from the upper mold 201 and lower mold 202, thereby obtained thepolarizing lens illustrated in FIG. 14. The removed lens by mold releaseincluded the polarizing film 7 interposed between two pieces of the lensbase material. The obtained lens was the polarizing lens where thepolarizing film was interposed between lens base materials made ofpolyurethane with a refractive index of 1.67 and Abbe number of 32. Thelens power was 1.00 dioptres.

(Surface Treatment)

As a surface treatment, a hard coat and anti-reflection film were formedby the following method.

The polarizing lens 7 was subjected to hard coat treatment by animmersion method using coating liquid containing colloidal silica withan organosilicon compound as a matrix component. The speed of pulling upwas 26 cm/min. After application, air-drying was performed at 80° C. for20 minutes and then baking was performed at 130° C. for 120 minutes. Thethickness of a cured coating film obtained in this manner wasapproximately 2 μm.

Next, on the polarizing lens 7 applied with the hard coat treatment, ananti-reflection multilayer film including five layers of SiO₂, ZrO₂,SiO₂, ZrO₂, and SiO₂ in an order from the lens base material toward theatmosphere was formed by a vacuum vapor deposition method.

The first layer of SiO₂ layer, a subsequent equivalent film layer ofZrO₂ and SiO₂, still subsequent ZrO₂ layer, and the upper most SiO₂layer were formed such that an optical film thickness of each of theabove equals λ/4. Incidentally, a design wavelength λ was 520 nm.

(Edging Processing)

Next, edging processing was performed on the lens of a round shapeapplied with the aforementioned surface treatment using a lens shapeprocessing device (GE-5000, manufactured by HOYA CORPORATION) such thatthe lens corresponds to a lens shape of a specified spectacle frame(FIG. 1), thereby obtained a cut lens.

(Hydrophobization Treatment (Edge Surface Treatment)

The whole polarizing lens having been subjected to the edging processingwas immersed in 60 ml of an aqueous solution of formaldehyde (at aconcentration of 7 mass %), to which 12 ml of hydrochloric acid of 32mass % was added and then left at 70° C. for 20 minutes. Here, theaqueous solution may arbitrarily stirred. Adding hydrochloric acidinitiates acetalization. Acetalization of polyvinyl alcohol proceedsfrom a part exposed at the edge surface of the lens.

Thereafter, the polarizing lens pulled out from the aqueous solution offormaldehyde was neutralized by an aqueous solution of sodium hydroxideand then rinsed with pure water. In this manner, obtained was thepolarizing lens having a region in the edge surface of the lens where anedge surface of the hydrophobized (acetalized) polarizing polyvinylalcohol film is exposed and having other regions applied withtransparent polishing processing.

Comparative Example 1

The polarizing lens was obtained by similar steps to those of theexample 1 except for the point that the hydrophobization treatment wasnot performed.

Example 2

The polarizing lens was obtained by similar steps to those of theexample 1 except for the point that a monomer capable of forming acommercial lens base material made of polyurethane with a refractiveindex of 1.60 and Abbe number of 42 was used as a lens monomer.

Comparative Example 2

The polarizing lens was obtained by similar steps to those of theexample 2 except for the point that the hydrophobization treatment wasnot performed.

(Water Resistance Test)

The polarizing lenses produced in the examples and comparative exampleswere immersed in a thermostatic water tank with water set at 90° C. andthe lenses were pulled up at a certain time interval for observation ofchanges. When water resistance is not enough, the polarizing film isdecolored and colors change. When permeation of water further proceeds,the polarizing film dissolves into the thermostatic water tank. In caseswhere permeation of water was observed, a size (width of deterioration)of a part with changes from the edge of the lens to the center thereofwas measured in the unit of millimeter. A result therefrom isillustrated in table 1.

TABLE 1 WATER RESISTANCE TEST, WATER AT TEMPERATURE OF 90° C. REFRACTIVEWIDTH OF DETERIORATION INDEX OF ACETAL (UNIT: mm) RESIN TREATMENT 5HOURS 24 HOURS EXAMPLE 1 1.67 PERFORMED 0.0 1.7 EXAMPLE 2 1.60 PERFORMED0.0 2.1 COMPARATIVE 1.67 NOT 1.2 6.2 EXAMPLE 1 PERFORMED COMPARATIVE1.60 NOT 0.9 7.4 EXAMPLE 2 PERFORMED

From a result in Table 1, in the examples 1 and 2, suppression ofdeterioration due to permeation of water can be confirmed since the partof the polarizing polyvinyl alcohol film exposed at the edge surface ofthe lens were acetalized and thus hydrophobized.

Further, FIG. 15 is a picture, imaged by a digital camera, of a part cutout from the polarizing lens produced in the example 1 after the waterresistance test (24 hours).

FIG. 16 is a picture, imaged by a digital camera, of a part cut out fromthe polarizing lens produced in the comparative example 1 after thewater resistance test (24 hours).

As illustrated in FIG. 15, the polarizing lens produced in the example 1was uniform even after the water resistance test of 24 hours. Contraryto this, as illustrated in FIG. 16, the polarizing lens produced in thecomparative example 1 showed discoloration and color changes of thepolarizing film at an outer periphery part of the lens after the waterresistance test of 24 hours.

In this manner, according to the present invention, the polarizing lenswhere the polarizing polyvinyl alcohol film is exposed at the edgesurface of the lens can prevent permeation of water from the exposedpart, thereby preventing deterioration of the film.

(Frame Fitting)

The polarizing lenses produced in the examples 1 and 2 were attached totwo-point frames and rimless spectacles were obtained.

Note that when the lens is a semifinished lens, a concave surface issubjected to grinding/polishing processing by a curve generator andpolishing device after mold release to allow the concave surface to meetprescriptions to obtain an eyesight corrective spectacle lens.

Examination on Heating Temperature of Polarizing Film after CurvedSurface Processing

<Production of Sample Lens 1>

1. Wetting Treatment, Curved Surface Processing, and Subsequent HeatingTreatment of Polarizing Film

A commercial dichroic dye-based polarizing film made of PVA was arrangedin a humidistatic high temperature device and subjected to the wettingtreatment and thereby allowed to be wet such that a water content at thestart of curved surface processing equals 4%. The wet polarizing filmwas left at a room temperature (20 to 25° C.) for approximately twominutes and then subjected to the curved surface processing in theaforementioned method explained based on FIG. 8. The curved surfaceprocessing was also performed at the room temperature.

Next, the polarizing film having been subjected to the curved surfaceprocessing was heated at 120° C. for 30 minutes using a commercial hotair circulating oven. Heating was performed without using the curvedsurface processing plate (glass mold) 160.

2. Molding of Lens by Cast Polymerization Method and Mold Release

Plastic lens raw materials of 50.6 g of m-xylene diisocyanate and 49.4 gof 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-tri-thiaundecane weremixed and stirred sufficiently.

An ultraviolet light absorbent of 1.2 g of “SEESORB701” (trade name,manufactured by SHIPRO KASEI KAISHA, LTD.) and an internal mold releaseagent of 0.1 g of “internal mold release agent for MR series” (tradename, manufactured by Mitsui Chemicals, Inc.) were further added, mixed,and sufficiently stirred. In the plastic lens raw materials completelydispersed or dissolved, a catalyst of 100 ppm of dibutyltin dichloridewas added and sufficiently stirred at a room temperature to obtainuniform liquid and a composition therefrom was stirred under reducedpressure of 5 mmHg and subjected to deaeration for 30 minutes, therebyproduced a lens monomer.

Into the forming mold, where the polarizing film having been subjectedto the heating treatment of the above #1 is arranged therein, theproduced lens monomer was injected. A surface shape of the upper moldand lower mold was spherical with an inner diameter of 80 mm and aradius of curvature of 130.4 mm.

Thereafter, the forming mold was placed in a heating furnace, retainedat 30° C. for seven hours, and then subjected to temperature elevationfrom 30 to 120° C. in 10 hours, thereby performed heating and curing.

After the heating and curing, the forming mold was removed from theheating furnace. The lens was removed from the forming mold, therebyobtained the lens (semifinished lens). Subjecting a concave surface ofthe lens to grinding/polishing processing by a curve generator andpolishing device allows for obtaining an eyesight corrective spectaclelens that meets prescriptions.

<Evaluation of Optical Performance of Lens>

In order to evaluate deformation of lens after mold release (in a rounduncut state), optical performance was evaluated according to thefollowing items. Note that examination by visual inspection wasperformed by an inspector having three or more years of experience inlens examination. An evaluation result was as illustrated in Table 2.

(1) Deformation of Shape

The maximum radius of curvature (mm) (Rmax) and minimum radius ofcurvature (mm) (Rmin) at the geometrical center point on the convexsurface of the lens (namely, optical center) were measured by acurvature radius measuring apparatus “FOCOVISON” (manufactured byAutomation & Robotics).

A curvature difference between the maximum radius of curvature (mm) andminimum radius of curvature (mm) (Rmax−Rmin) was used as an index oflens deformation (astigmatism) and evaluation was performed in thefollowing manner. Note that the convex surface of the lens is designedto be spherical and the geometrical center on the convex surface is apoint of intersection of a perpendicular, passing through the center ofa circle when the lens is seen from a planar view, and the lens convexsurface side of the lens.

A curvature difference of 0 to less than 3 mm: ◯ (passed), 3 mm to lessthan 4 mm: Δ (slight deformation acknowledged but no problem for use),and 4 mm or more: x (difficult to use).

(2) Color Change of Polarizing Film

Whether there is a color change in the polarizing film 7 in the lens wasconfirmed by visual inspection.

No color change: ◯

Color change without change in hue acknowledged: Δ

Color change with apparent change in hue acknowledged: x

(3) Distortion of Polarizing Film

Distortion of the polarizing film (deformation of a surface shape) inthe lens was examined by visual inspection (an inspector having three ormore years of experience in lens examination).

No distortion acknowledged at all: ◯

Distortion acknowledged at a part of periphery of the lens but noproblem for use: Δ

Distortion acknowledged at a glance: x

Total Evaluation

The lens that showed no result of x in any items of the deformation oflens, color change of polarizing film, and distortion of polarizing filmwas evaluated as ◯ while the lens showed at least one result of x wasevaluated as x. The lens showed a result of ◯ at every evaluation itemwas evaluated as ⊙.

<Sample Lenses 2 to 5 and Reference Lenses 1 to 4>

Each of the sample lenses and reference lenses was produced in a similarmanner to that of production of the sample lens 1 except for a pointthat heating of the polarizing film having been subjected to the curvedsurface processing was performed under conditions shown in Table 2. Notethat the reference lens 1 was used without heating the polarizing film.

<Sample Lenses 6 and 7 and Reference Lenses 5 and 6>

In production of the sample lens 1, instead of a commercial dichroicdye-based polarizing film made of PVA, a commercial laminated polarizingfilm (TAC/PVA) including protective layers made of TAC on both surfacesof a dichroic dye-based polarizing film made of PVA was used. Each ofthe sample lenses and reference lenses was produced in a similar mannerto that of production of the sample lens 1 except for a point thatheating of the polarizing film was performed under conditions shown inTable 2.

<Sample Lens 8>

The lens was produced in a similar manner to that of production of thesample lens 2 except for a point that heating was performed while thepolarizing film was retained by the curved surface processing plate 160used in the curved surface processing.

TABLE 2 HEATING CONDITION OF POLARIZING FILM HEATING HEATING POLARIZINGGLASS TEMPERATURE TIME Rmax Rmin Rmax − Rmin FILM MOLD (° C.) (HOUR)(nm) (nm) (nm) SAMPLE PVA NOT 120   0.5 129 127.9 1.1 LENS 1 USED SAMPLEPVA NOT 120 2 129 126.3 2.7 LENS 2 USED SAMPLE PVA NOT 130 2 129.7 126.92.8 LENS 3 USED SAMPLE PVA NOT 105 2 130.1 126.6 3.5 LENS 4 USED SAMPLETAC/PVA NOT 140 2 128.9 128.1 0.8 LENS 5 USED SAMPLE TAC/PVA NOT 120 2129 127.8 1.2 LENS 6 USED SAMPLE PVA NOT 140 2 129.2 128 1.2 LENS 7 USEDSAMPLE PVA USED 120 2 129 127.7 1.3 LENS 8 REFERENCE PVA NOT — — 135.7127.9 7.8 LENS 1 USED REFERENCE PVA NOT  60 5 136.1 128.1 8 LENS 2 USEDREFERENCE PVA NOT 100 5 132.4 127.8 4.6 LENS 3 USED REFERENCE PVA NOT150 2 129.5 128 1.5 LENS 4 USED REFERENCE TAC/PVA NOT 100 2 136.5 126.510 LENS 5 USED REFERENCE TAC/PVA NOT 150 2 129.5 128 1.5 LENS 6 USEDCOLOR CHANGE OF DISTORTION OF DEFORMATION POLARIZING POLARIZING TOTALSAMPLE OF LENS FILM FILM EVALUATION LENS 1 ◯ ◯ Δ ◯ SAMPLE LENS 2 ◯ ◯ Δ ◯SAMPLE LENS 3 ◯ ◯ Δ ◯ SAMPLE LENS 4 Δ ◯ Δ ◯ SAMPLE LENS 5 ◯ Δ Δ ◯ SAMPLELENS 6 ◯ ◯ Δ ◯ SAMPLE LENS 7 ◯ Δ Δ ◯ SAMPLE LENS 8 ◯ ◯ ◯ ⊙ REFERENCELENS 1 X ◯ Δ X REFERENCE LENS 2 X ◯ Δ X REFERENCE LENS 3 X ◯ Δ XREFERENCE LENS 4 ◯ X Δ X REFERENCE LENS 5 X ◯ Δ X REFERENCE LENS 6 ◯ X ΔX

As illustrated in Table 2, the sample lens 4 where the polarizing filmhaving been subjected to the curved surface processing was heated at105° C. had a curvature radius difference (Rmax−Rmin) of 3.5 mm.Further, the sample lenses 5 to 7 where the polarizing film was heatedat 140° C. showed a color change without change in hue; however, any ofthe sample lenses showed no practical problem for use as the polarizinglens.

Moreover, it became clear that heating at 120° C. to 130° C. can providea lens with superior optical performance and appearance wheredeformation of the lens or color change of the polarizing film isreduced.

The sample lenses 6 and 7 using the laminated polarizing film alsoshowed similar results, which made clear that using a polarizing filmheated under similar conditions can suppress deformation of lens shapeeven with other films without limiting to the PVA film.

Contrary to this, the reference lenses 1 to 3 and 5 had a curvatureradius difference (Rmax−Rmin) of 4 mm or more and showed seriousdeformation of lens shape. Any of the reference lenses 1 to 3 and 5 wassubjected to a heating temperature of less than 105° C. This shows thatshrinkage of the polarizing film before injection of a polymerizablecomposition as a lens base material may not be sufficient. This may havecaused shrinkage of the polarizing film upon heating and curing andthereby caused deformation in the lens.

Furthermore in the reference lenses 4 and 6, the polarizing film washeated at 150° C. and thus deformation of the lens was suppressed butthe polarizing film was deteriorated and a color change occurred.

In the sample lenses 1 to 7 where the curved surface processing plate160 was not used, a shape of the polarizing film was slightly distorted.On the other hand, in the sample lens 8 where the curved surfaceprocessing plate 160 was used, the lens having a superior opticalperformance with suppressed distortion was obtained.

Therefore, it became clear that heating while the polarizing film isretained by the curved surface processing plate 160 can suitablysuppress deformation of the shape and distortion of the polarizing filmand allows for obtaining the lens with better appearance.

From the above results, heating the lens having been subjected to thecurved surface processing at a predetermined temperature is confirmed toallow for providing the polarizing lens with less deformation of thesurface shape thereof that causes astigmatism.

Further, heating the polarizing film having been subjected to the curvedsurface processing while the polarizing film is retained by the curvedsurface processing plate 160 used for the curved surface processing cansuppress change, from a design shape, of a shape of the curved surface161 a (c.f. FIG. 8(A)) of the polarizing film. Therefore, the polarizinglens with more preferable appearance can be manufactured.

Combining the curved surface processing as described above and thehydrophobization treatment described in detail earlier allows forobtaining the polarizing lens of an extremely high quality wheredeterioration of an outer periphery part of the polarizing film anddeformation of s surface shape of the lens are both suppressed.

INDUSTRIAL APPLICABILITY

The present invention is useful in the field of manufacturing variouseyewear such as spectacles and a polarizing lens for eyewear.

1. A method comprising: subjecting a polarizing lens to edgingprocessing, wherein the polarizing lens includes a polarizing polyvinylalcohol film arranged between two pieces of a lens base material, andthe polarizing polyvinyl alcohol film is exposed at least at a part ofan edge surface of the lens; and applying hydrophobization treatment tothe polarizing polyvinyl alcohol film exposed at the edge surface of thelens.
 2. The method according to claim 1, wherein the hydrophobizationtreatment is applied after the edging processing.
 3. The methodaccording to claim 1, wherein the hydrophobization treatment includesimmersing the polarizing lens in a solution containing a hydrophobizingagent having a functional group that reacts with a hydroxyl group. 4.The method according to claim 3, wherein the solution further includes areaction catalyst, an acid, or a base.
 5. The method according to claim1, wherein the hydrophobization treatment is performed by contacting thepolarizing polyvinyl alcohol film exposed at the edge surface of thelens with a hydrophobizing agent having a functional group that reactswith a hydroxyl group.
 6. The method according to claim 5, wherein thehydrophobizing agent is a compound that reacts with polyvinyl alcoholvia a reaction selected from the group consisting of a cross-linkingreaction, a dehydration reaction, and a halogenation reaction.
 7. Themethod according to claim 6, wherein the hydrophobizing agent is ahydrogen halide.
 8. The method according to claim 6, wherein thehydrophobizing agent is at least one selected from the group consistingof an alcohol, a carboxylic acid, and a silanol.
 9. The method accordingto claim 6, wherein the hydrophobizing agent is a cross-linking agent.10. The method according to claim 9, wherein the cross-linking agent isaldehyde, and the cross-linking reaction is acetalization.
 11. Themethod according to claim 10, wherein the aldehyde is at least oneselected from the group consisting of formaldehyde, acetaldehyde,glyoxal, and glutaraldehyde.
 12. The method according to claim 11,wherein the aldehyde is formaldehyde.
 13. The method according to claim10, wherein the acetalization occurs in the presence of an acid.
 14. Themethod according to claim 13, further comprising, after thehydrophobization treatment, treating the polarizing lens with a base.